What suggestion is made about the fomer purpose of the various ruins he could see?

A、They had formed part of the capital of a new iMayan Kingdom.
B、They were what remained of a temple to sky gods.
C、They were what was left of the starting-point from which the Mayans had moved to new territory.
D、They were what remained of the farthest city reached in a large-acale Mayan migration.